Nonresonant system



June 8 1926.

R. V. L. HARTLEY NoNREsoNANT SYSTEM Filed Feb. 5, 1919 /6 dlg/0136.]

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$ in a circuit be' Patented` `Func 8 17926.

UNITED STATES PATENT ori-ica- RALPH Vf. L. HARTLEY, OF EAST ORANGE, NEWJERSEY, ASSIGNOIB TO WESTERN ELEC- TRIO COMPANY, INCORPORATED, OF NEWYORK, N. Y., A CORPORATION OF NEW YORK.

N ON RESONANT SYSTEM.

This invention relates to methods and means for generating alternatingcurrents.

A well-known type of oscillation generator is that. in which one or moretuned circuits t containing inductance and capacity, in whichoscillations are to be produced, are associated with a highly evacuatedelectron discharge device havingan anode, a. heated electron emittingcathode, and an impedance varying 10 element. Such a device is commonlyknown jas an audion and functions to set up and maintain the desiredoscillations. The fre uency or frequencies of the oscillations pro ucedby such an arrangement will depend principally upon the tuning of thetuned circuit or circuits.

It lias'been found, however, that it is possible to construct such agenerator withr out a tuned circuit, thev fr uency 'of the generatedoscillations beingedetermined by the magnitude of the electricalconstants of certain other elements included in the arrangement. Theperiod of any inherently unstable system whose condition changescyclically is general a function of the stiffness factor and the'inertia. factor of the system. Any such system wherein one orthe otherof these factors is negligible may be styled a non-resonant system. a0The expression non-resonant generating system, as hereimapplied toelectrical systems, is intended to define a generating system in whichoscillations are set up by virtue of electrical energy from a source ofeuri ent alternately stored up by a reactance and discharged, the

means/,'-capacity and inductance. Incase 40 both capacity and inductanoeare included in sucha system they are .so related as not to constitute aresonant circuit and thereby determine the oscillation frequency. v

An -ob'ect of the invention is to provide improve arrangements wherein,one or a plurality of'- impedance Vvarying devices,V

n uency of vthe generated oscillations being in ependent' of one oftheusual frequency determining.

and lany incidental inductance of the connecting conductors beingnegligible and Wholly unessential to the operation of the provide such ato an impedance elegeneration of symmetrical osa pair of amplifiers' Afurther object is to rovide means suchA Y as herein describedwhere yalternating current of non-sinusoidal wave form as,for example,flat-topped or other symmetrical waves, may be reduced.

.A further o je'ct is the provision of eicient means for the productionof low frequency oscillations.

A Other objects are the provision of various i improved details tendingtoward the production of simple, efficient, stable and easil adjustablenon-resonant generators, as wi appear after consideration of thefollowing detailed description. Certain novelifeatures ofthe describedsystems, moreover, are of lutility in other than generating systems andI are therefore claimed broadly. l The invention is illustrated in theaccompanying drawing, wherein Fig. 1 represents a form of non-resonantgenerator inwhich two discharge devices and a capacity are included;Fig. 2, a similar form in which ind'uctance elements but no capacitiesare used; and Fig. 3, a modification of Fi 2 in which only. one of thetwmsymmetrica y arranged halves ofthe system of Fig. 2 is employed.

In Fig. 1 the anodecathodecircu1t 2 of the vacuum tube or audion 1includes the variable resistance 3, a source of current 4,variableresistance 5, and condenser 6. The anode-cathode circuit of tube7 includes variable resistanoe 8, source 9, resistance 10 and condenser6. Under certain conditions the resistances 3 and 8 may be of small orzero value. The condenser 6 is connected to the anode-cathode circuit ofone of the tubes in a manner opposite to' that in which it is connectedto the anode-cathode` circuit of the other. The input circuit 11 of.tube 1 so includes .the resistance 10 that increase of current throughtube 7 and resistance 10 makes the grid of tube 1 more negative. Theinput circuit 12 of tube 7 is connected to the resistance 5 in acorresponding man-ner.

Batteries 13 are provided for AMA il@ alternating electromotive torceproduced lll thereby any suitable "means, -tor example, an output line16,. may he connected to the system in any suitable manner, as, for eX-auiple, across the condenser 6.V 'lhe output line leads to any loadtranslating device 17. A therrnionic repeater 18 may be connected in theline 16 because ci its unidirectionally conducting propertiesandarnplifying povver. rlhe device 18 serves to rovide increased currentof the generate Wave form andY to prevent reaction of the translatingdevice upon the generating system.

@parution of the system of Fig' I.

'Suppose the' circuit is so designed and the elements so proportionedthat an increase in current e", through tube l causes a suciently largediderenceoi potential be-v tvveen the terminals ot resistance 5', that'dou' ci current ,i2 through tube 'i' vvi'llbe reduced to zero or asmall value. Similarly,

an increase oi current c, vvill vcut ed' or substantially reduce thecurrent 'il through tube 1i Assume, moreover, a disturbance ofequilibrium-V whereby the condenser V6 is charged as indicated in thedrawing, then the volta-ge across condenser 6 is added to i' thatnormally em'sting in the anode-cathode circuit ot tube 1 and issubtracted troni that in the anode-cathode circuit oi tube i?. As aresult, il is increased and @"2 decreased. rlhe w' increase in i cuts edi2 or reduces it to a V'sinaller value. lhis in turn, by removing thevoltage across resistance 10, tends to increase n1 still more. As e", isincreased, all

the current c", must be supplied hom the condensen "so that the voltageacross the VV/ 'Y tential above its average value and the ggg'ridcondenser decreases. Upon reaching the normal or uncharged condition,the Ycon'- denser 'becomes` charged in theopposite direction becausewhen the charge upon Vcondenser 6 has reached aero.l c", is stillgreater ont tube i a lower value. Consequently, it

Ais-not until the charfin ci the condenser in till' the'reversedirection has`Y reduced the anodecathode voltage across the tube 1 to avalue where the current through tube l begins to decrease, that the gridvoltage ot the tube 7 becomes high enough or suciently reduced ihrem anegative value, that current i2 begins to flow 'or increase. Ais soon asthis happens, the vincreasedpotential'difterence across resistance 10cuts oil' i1. Simultaneously 2 is further increased by the increase'`ol.grid voltageimdue to .the decrease ot potential dierence between theterminals or resistance 5. rlhis process continues indenitely and hencean alternating potential dilierence is produced across the terminals ofthe condenser 6.' While this potential diderence may in sonic instancesbe directly appliedv to a translating device, it vvill be advantageousto provide a potential-operated repeating device 18 Whose output circuitsupplies the current to be utilized. 'lhe unidireotionally conductingproperties oli` the device 18 serve to prevent variationsof electricalcondition of the load device 17 from 'aecting the oscillatory conditionot the generating system. `Whilc the device 18 vvill produce a smallcapacity ef- -fect in parallel With capacity 6, this will usually benegligible.

rlhe generated Wave form will tend to be syetrical and `square-toppedrather than sinusoidal and will approach a more nearly sinusoidal tornias the amplitude is de- `creased, vvhich inay be accomplished byincreasing the resistances 3 and 8 or decreasing the mutual impcdancesbetween the tvvo tubes, i. e. resistances 5 and 10. The :trequency isdependent to some extent upon every constant ot the system but it may bevaried over a considerable range by variations in capacity 6.

The system ot h ig. 2 utilizes inductances but no capacities. 1lheelements in general correspond to those described in connection withlig. 1, as vvill be seen by comparison ci the corresponding referencenumbers. However, inductance 20 is substituted Y :for the capacity 6.'lhe inductances 21, 22

are coupled to inductance 20 in such a inanner that increase et currentin the direction et the arrovv through inductance 2O makes the grid citube 1 less negative and the .grin ot' tube 7 ymore negative. systemthere 'tore depends for its operation upon the electromagnetic inductionbetween the input and output circuits. 'lhe action will be proved bydesig the system so that elec'- lil trostatic edects will be reduced toa minimura.

@poration of the' aystem of Fig. f2.

Assume an increasing current iiowing in the direction ot the arrow.rlhis makes the grid ot tube 1 more positive and the grid of tube 7 morenegative. lhe impedance ot tube 1 is therefore decreased and of tube 'i'increased. Current through tube l is turther increased up to somemaximum value as determined by resistance 8, constants of tube y1, andthe potentials oi batteries 4 and 13.

its soon as the current through the tube 1- positive or more negative,.as the case may be,

' Grease.

amount of the .energy since it is the increased otential-in a positivesense-on the grid) of tube 1,; which lowers the impedance of the tubesufficiently to`allow the increased current to pass therethrough. Assoon as the positive otential on the,grid ceases to be maintains the in.

creased flow of current cannot be maintained.

As lsoon las the current begins to decrease,

-the transformer action between coils 20 and 21 decreases the otentialof the grid of tube 1, thereby'stil further decreasing the current.Meanwhile, the grid of tube 7 has become more positive-or lessnegative-and the current through it begins to flow or in- Thelast-mentioned current is in a direction in the coil/20 opposite to thatin which the cur-rent throu h tlie tube 1 flows. When the current'througthe tube 7 exceeds that through the tube 1, the current through the coil 20 reverses and a cycle of operations occurs'in the tube 7 similarto that described for the tube 1.. This action willV be maintainedindefinitely, rovided the total issipated in the System and lin theoutput circuit 16 is not too -prising one of' the symmetrically arrangedhalves of the system .of Fig. 2. The operation ofthis system is similarto that of the system of Fi 2. The inductances 20, 21 must, as in t earrangement of Fi/g. 2, be coupled so that increasing current throughcoil 20 in the direction of the arrow, renders the grid of tube 1 morepositive or less negative. The amplitude and frequency may be regulatedby varying the electro,- motive force of source 4, resistance 3,Ainductance 20, 421 and the mutual inductance therebetween. Inasmuch asthe electrostatic inductive effect between the grid'and the anode of thetube 1 may tend to cause the device to produce oscillations in a manneranalogous to previously known types of oscillation generators with afrequency de ending upon the capacity, between the gri and *the anode oftubel, and the inductances 20, 21 and the mutual inductancetherebetween,

` the variable elements of the system areso adjusted as to preventthisaction. Imgen-v eral, this may be accomplished by adjusting the systemso that the mutual conductance between` the grid and plate circuits istoo small tosup ort undesired oscillations of the fr uen'cyfvyv ich tendto occul.. The mutual .con uctai'i'ce may be reduced in various wayswhich are known to those skilled in the art,

such as changing-the coupling'between coils 20 and 21, making theinductancsof coil 21 .relatively sinallQ or b increasing the resistance3. Undesirab e oscillations of any frequency which tend to occur will beof relatively high frequency because of the small magnitudes of thegrid-plate capacity, the other internal capacities of the tube and the1distributed capacities ofthe associated coi s.

The novel features inherent in tlie iiivcntion are defined 'in theappended claims.

lVhat is lclaimed is:

1. A non-resonant oscillation generator comprising a pure electrondischarge device, an anode, a cathode, and an impedance s controllingelement therefor, an output circuit connected-to the anode and tliecathode, a. feed-back connection from tlie output circuit to theimpedance controlling element,

said output circuit containing a iesistance externa-l to said device,said output circuit containing react-.ance of one kind only which iseffective in controlling the frequency of the oscillations generatedL 2.A generating system` comprising a series circuit, said sciies circuitcontaining consecutively arranged current sources, anodes, andelectron-emitting cathodes, said sources being so connected as to tendto drive current in tli'esanie direction through said circuit, incombination with a frequency de- V termining. reactance. Fig. 3illustrates a system employing a d single discharge device or amplifierand com- 3. A system Acomprising a plurality of 'ielectron-dischargerepeaters, means tending vto drive current through each repeater, and

tablishing the periodicity of said generator.

5. A non-resonant oscillation generator comprising an energy storingelectric capacity and an energy dissipatin device vof negligibleinductance connected t ereto, said dissipating device and the electriccapacity constituting a non-resonant requenc determining circuit, and anelectric disc arge device for periodically reversing the current flow inthel circuit comprising said energy dissipating device and said energystoring electric capaeity.

6. A nonigesonant oscillation generator comprising electron dischargemeans, impedance controlling means therefor, and a capacity-f connectedto saidi discharge means,

saidcapacity being included in a non-resonant frequency determiningcircuit. i

7. A non-resonant os-icillation,v` generator comprising a lhighly'evacuated el`ectroii discharge tube, a capacity, and conneptinimpedance means, said capacity land sai impedance means constituting anon-resonant frequency determining circuit.

- and' charged 8. A non-resonant oscillation generating systemcomprising a pair ot thermionic discharge tubes having anodes, circuitsthereit'or, and a capacity oppositely connected conductively tocorresponding anodes ol said tubes by conductors of negligibleinductance. 9. An electrical system comprising a network ot circuitshaving several conductive paths in an unvarying state of continuity, acapacity in said system, and means whereby said capacity is successivelycharged through one of said paths and discharged through another path,said last mentioned paths having their common portion of negligibleimpedance except for the impedance of said capacity.

10. A system comprising a network of circuits having severalunsymmetrically conducting branches in an unvarying state of continuity,a capacity in said network, and means whereb said capacity is dischargedby each of said branches in succession and impedance controlling meansfor varying the discharge through each of said branches.

11. A system comprising a pair of vacuum tubes each having an anode, acathode and an impedance-varying element, a capacity connecting saidcatliodes, anodecathode circuits for each of said tubes, each of saidcircuits containing said capacity and two resistances, an input circuitforeach ot said tubes, each input circuit comprising one of saidresistances in the anode-cathode circuit of the other tube, a waveutilizin circuit connected across said capacity, t?

a voltage operated unidirectionally transferring device for current insaid utilizing circuit.

12. A system comprising a capacity, a

plurality of unidirectionally conducting paths having negligibleinductance connecting the terminals of said capacity, andy means wherebycurrent-flow in one of said paths tends to increase the impedance ofanother of'said paths.

13. A system comprising a capacity, a plurality of unidirectionallyconducting pathsfof negligible inductance connecting the terminals ofsaidv capacity, and means whereby variation in current-ilow-in-one ofsaid paths causes simultaneous variation in impedance of anotherof saidpaths.

14. An oscillation generator comprising a branched circuit, a source ofcurrent in said circuit, a capacity in one branch of said circuit, animpedance-varying device rin each lof a plurality of said branches,means assoeiated with each of said impedance-varying devices responsiveto current in saidv circuit forcontrolling the impedance-varying devicesrespectively, and means for determining the frequency of oscillationssubstantially independent of inductive reactance.

15.",A non-resonant oscillation 'generator comprising 'a space dischargedevicejhaving an electron emitting cathode, an anode,

stant primarily determines the frequency of said generator.

16. An electrical system comprising a pair u of space discharge devices,a branch circuit having capacitative reactance at all frequcncics, andmeans whereby the direction A ot current flow through said branchdetermines the relative impedance of.' said devices.

17. An electrical generating system comprising means for establishing aplurality of electron streams in space, an electrostatic control meansfor each stream, a path having reactance of the same kind for a largerange of frequencies both above and below the generated frequency inseries with the space path of each stream, and means controlled by thcdirection and intensity of current `in .said path for acting on saidstreams through said control means.

18. ln thermionic apparatus, the combination of a plurality of ionictubes, each having a filament, a gridand an anode, connections includingsources of current be,

tween the anode 'of one tube and the grid of a second'tube in saidapparatus, and between the anode of said second tube and the grid ofsaid first mentioned tube, and a.

common branch connection including high ohmic resistances in the anodeand grid circuits of both of said tubes, whereby the anode of one tubeand the grid of the second tube in said apparatus are connected, and theanode of said second tube and the Vgrid of the first mentioned tube areconnected, to form a closed circuit cascade system.

19. In thermionic apparatus the combif nation comprising a lurality fthermionic l tubes each having a ament, a grid and an anode, anode andgrid circuits for said tubes, the grid circuit of one tube beingconnected to the anode circuit of a secon tube, whilst the grid circuitof the second tube is connected to the anode circuit of the first tube,a plurality of hi vl1 ohmc resistances, one of the resistances singineluded in the common branch for the anode circuit of the first tubeand the grid circuit of the second tube, and one of the high ohmicresistances being included in the common branch for the anode circuit ofthe second tube and the grid circuit of the first tube. l

21. In thermionic apparatus comprising a plurality vof thermionic tubes,each havin Aa filament, a grid and an anode, anode an id cirgridcircuits for said tubes, the

to the cuit of one tube being connecte anode circuit of a. second tubewhile the' tube and the grid circuit of the second tube andthe other ofthe high ohmic rsistances being included in the common branch for theanode circuit of the second tube and the grid circuit of the first tube,means connecting the grid of a third tube included in the apparatus tothe anode circuit of the first tube and the filament of the third tubeto the anode circuit of the second tube, said connections 'being suchthat the electromotive forces set up in the first two tubes are appliedto the grid filament circuit of the third tube and effect changes in theanode circuit of said third tube.

In witness whereof, I hereunto subscribe my name this 30 day o f JanuaryA. D., 1919.

RALPH V. L. HARTLEY.

